Magnetic door catch



April 11, 1967 w. J. BRINK MAGNETIC noon CATCH Filed March 31, 1965 INVEN TOR.

WILLIAM J. BRINK FIG ATTORNEYS United States Patent C) 3,313,565MAGNETIC DOOR CATCH William J. Brink, Box 218, Bainbridge Island, Wash.98110 Filed Mar. 31, 1965, Ser. No. 444,141 8 Claims. (Cl. 292-2515)This invention relates to a magnetic catch in which a permanent magnetsmagnetic attraction for an armature is relied upon to establish alatching hold. Magnetic catches find their greatest usefulness insecuring swinging doors of cabinets and the like, with the pennanentmagnet being carried by a housing which is usually attached to astationary Wall of the cabinet and with the armature comprising a strikeplate which is usually carried by the door.

If a magnetic catch is to perform its intended function to the bestadvantage it is necessary that the housing and the strike plate be somounted upon the cabinet that the door is brought to bear against theedge of the outer wall of the cabinet precisely at the very moment thatthe strike plate contacts the permanent magnet. Should any gap remainbetween the strike plate and the magnet the effective magneticattraction is perforce lessened and the magnet, which commonly is givena pivotal mounting within the housing, remains loose and can be subjectto annoying vibration. When installing a magnetic catch it is usual toscrew the housing piece to the underside of a shelf of the cabinet.Heretofore, the screws have 'been received through slots extendingnormal to the front edge of the shelf in order to permit fiore-and-aftadjustment of the housing and by means thereof positioning the magnet sothat the same will protrude in the degree necessary to be engaged by thestrike plate at precisely the right moment. A certain amount of trialand error is required, and it is perforce necessary to loosen the screwsbefore and again tighten the screws after each adjustment. Thisconventional manner of mounting the housings is disadvantageous forseveral reasons. Repeated turning of a screw mutilates the holes inwhich the same are threaded. The grip becomes loose. The striker platemay then cause the housing to shift position and aggravate the loosenesswith each opening and closing of the door, pulling the magnet outwardlyand pushing the same inwardly within the limits prescribed by the lengthof the slots.

The principal object of the present invention is to devise a magneticcatch in which the armature forming striker plate is formed as the flathead of a screw and produces the necessary adjustment by the degree towhich it is threaded into the door of the cabinet. This advanced mode ofadjustment permits the magnet housing to be secured by screws which passthrough mating circular holes rather than the described slots. Impactbetween the striker plate and the magnet passes only an inconsequentialshear force into the screws which firmly anchor the housing and acompressive force into the threaded stem of the striker plate.

It is a further object, and one which requires an elimination of theslots for its best realization, to provide a magnetic catch in which themagnet housing can be fixedly secured to the shelf of a cabinet in asingle operation by pressure exerted from the jaws of clamping pliers.

As a yet additional and important object the invention aims to providefor the magnet a perfected housing which is of simple and inexpensiveplastic composition, and one in which the magent can be assembled withgreater ease and expedition than has been heretofore possible.

With the foregoing and other more particular objects and advantages inview the invention consists in the novel construction and in .theadaptation and combination of parts hereinafter described and claimed.

In the accompanying drawing:

FIGURE 1 is an exploded perspective view illustrating the several partswhich comprise the magnetic catch of the present invention.

FIG. 2 is a fragmentary longitudinal vertical sectional view through theshelf and door of a cabinet and illustrating, in side elevation, thehoused magnet and the striker plate of the present magnetic catchinstalled thereon.

FIGS. 3 and 4 are a fragmentary transverse vertical and a fragmentarylongitudinal vertical sectional view showing the manner in which aspecial pair of clamping pliers are employed to install the housedmagnet upon the underside of a cabinet shelf, the planes on which thesections are drawn being shown at 3-3 of FIG. 4 and 44 of FIG. 3,respectively; and

FIG. 5 is a perspective illustration of the striker plate viewed from avantage point opposite that of FIG. 1.

The present invention follows the usual practice of employing a flatpermanent magnet having parallel top and bottom faces and cut to arectangular plan configmration, and sandwiched between upper and lowerpole plates. The pole plates, which are identical, are similarly flatand of rectangular plan configuration but have a foreand-aft depthsomewhat greater than the depth of the magnet. The numeral 1t) denotesthe magnet, and 11 and 12 the pole plates. Each piece has correspondingregistering circular holes, as 13, 14 and 15, cut in the substantialcenter thereof. Front and rear edges of the pole plates are ground fiatin a plane normal to the planes of the flat faces.

A housing which is molded from a suitable plastic material is formed tosomewhat of a U-shape to provide a floor Wall 16 flanked by parallelside walls 17, producing for the sandwiched magnet a stall which is openat the top, the front, and the back. The fore-and-aft depth is less thanthat of the pole pieces. The width of the stall moderately exceeds thewidth of the sandwich. The sides of the stall rise to a height somewhatgreater than the thickness of the sandwich. A hollow post 18 rises fromthe floor in a position centered both with respect to the width and thefore-and-aft depth of the stall. Other than for the post the floor ofthe stall is planar, and the parallel sides of the stall lieperpendicular to said planar face. The lower face of the door wall is ormay be progressively thickened from both side edges toward a rib 21located on the longitudinal median line of the housing.

Ears 20 project laterally from the outer face of each of the housingsside walls. The ears are rearwardly olfset beyond the transverse medianline of the housing land have their upper faces located flush with theupper edges of the side walls. Each ear is vertically pierced lay acircular hole 22. These holes are sized so as to provide a rather tightfriction fit for wood mounting screws. The heads 23 of the screws areexposed below the ears. Threaded ends of shanks 24 protrude well abovethe ears.

The post 18 has a height greater than the thickness of the sandwich butless than the height of the side Walls 17. Its diameter, is less thanthe diameter of the center holes 13, 14 and 15 which are formed in themagnet 11 and said complementing pole pieces 11 and 12, thus to permitthe components of the sandwich to float, so to speak, within the stall.The hollow center of the post, which is open at the top and closed atthe bottom, receives the stem 25 of a fiat-headed rivet. The rivet iscomposed of a material not subject to magnetic attraction, brass bypreference, and its stem has a friction fit in the post. The head of therivet has the function of holding the sandwich against dislodgment fromthe stall, thus is larger in diameter than the holes 13-14-15, and has alength such that its flat head 26 lies flush with the upper edge of theside walls when the rivet occupies the position, bottomed within thepost, in which it is shown in FIG. 4.

In assembling the parts the rivet can, but need not be, pressed fullyhome within the post. A special pliers, providing in one of its two jawsa slotted recess in which the housing seats, and having cupped openingsat each side of the recess accommodating the exposed heads 23 of themounting screws, permits the threaded shanks 24 of the screws to bedriven into the wood shelf S of a cabinet While coincidently bottomingthe rivet. Denoted by 27, said recessed jaw underlies the shelf whilethe other jaw 28 takes a bearing purchase upon the top face of theshelf. While not here illustrated, the pliers which I employ have acompound leverage which serves to maintain the floor of the recessedlower jaw parallel with the bearing face of the upper jaw throughout theopening and closing travel of the jaws.

The armature-forming striker plate 30 is formed as the head of a screw.The screw is made of magnetic material such as steel and its shank 31 isof the sheet-metal type, namely threaded throughout the length of auniform diameter other than for a sharp point. A 12-thread shank ofdiameter, A" in length, is suitable. The head is circular with a largediameter, say A", is fiat on both faces, and in the outer face presentsa socket 32 for the reception of a screw driver. The shank threads intothe door D of the cabinet so that the head lies in paralleling spacedrelation to the back face of the door in a position to engage themagnetic sandwich -1112 upon a closing of the door. Other than that thepole pieces of the sandwich should have a moderate exposure beyond thefront edge of the shelf, the particular placement of the housing uponthe shelf is unimportant in that the striker plate is enabled to be setat precisely adjusted positions by threading the same in or out. Whilenot here illustrated it is thought to be self-evident that the strikerplate, rather than being a single piece threading directly into the woodof the door, could be a Z-piece structure. The added piece would beimmovably secured to the door and provide a socket into which the shankof the striker plate would thread. The shank would be a threaded boltrather than a screw. An advantage in this Z-piece arrangement is thatthe threaded bolt, by the expedient of lining the socket in which itthreads with a bolt-gripping sleeve of nylon, would be assured ofholding a given setting over periods of long usage.

The invention and the manner of its use should be clearly understoodfrom the foregoing detailed description of my now-preferred illustratedembodiment. Minor changes in the details of construction can be madewithout departing from the spirit of the invention and it is accordinglymy intention that no limitations be implied and that the hereto annexedclaims be given the broadest interpretation to which the employedlanguage fairly admits.

What I claim is:

1. In a magnetic catch for holding the swinging door of a cabinetclosed, a permanent magnet sandwiched between pole pieces and eachformed from plate stock to a rectangular plan configuration, a housingof nonmagnetic material formed to provide an open-front stall in whichsaid sandwich is received with portions of the pole pieces projectingthrough said front opening and having means for retaining the sandwichin loose relationship with the housing, means for non-adjustablymounting the housing with its retained sandwich upon a wall of thecabinet to have the front edges of said projecting portions of the polepieces face outwardly proximal to and generally parallel with the innersurface of the closed door, and an armature plate for the magnet carriedby the door in a position to strike said front edges of the pole pieceswhen the door is swung into said closed position, the armature platebeing formed as the flat head of a screw having a comparatively longthreaded shank of a uniform diameter throughout very nearly its entirelength and; composed of a material attracted to the magnet and sothreadably mounted upon said door that the act of turning the screw inone direction advances the head toward and in the other directionretracts the head from said inner surface of the door, thus to positionthe head in a selected position adjusted toward or from said innersurface.

2. A magnetic catch as claimed in claim 1 in which the means forretaining the sandwich comprises a post rigid with the housing andextending loosely through centrally placed holes formed in the two polepieces and the magnet.

3. A magnetic catch as claimed in claim 1 in which the materialcomposing the housing is plastic, the housing having a general U-shapeproducing a floor and side walls for the stall and leaving the top andthe back as well as said front of the stall open, ears being providedextending laterally from said side walls each arranged to bear againstsaid cabinet wall on which the housing is mounted and each pierced by acircular hole accommodating a respective mounting screw.

4. A magnetic catch as claimed in claim 3 in which the holes whichpierce said ears are of a size to establish a' friction grip upon shanksof the related mounting screws.

5. A magnetic catch as claimed in claim 3 in which the two poles piecesand the magnet are formed with registering holes which fit loosely overa post which is made a rigid part of the housing and rises from thefloor of the stall.

6. A magnetic catch as claimed in claim 3 in which the two pole piecesand the magnet are formed with registering holes which fit loosely overa post which is made a rigid part of the housing and rises from thefloor of the stall, the post being hollow with an open top and having aheaded pin of nonmagnetic material press-fitted in the hollow center,the head of the pin having a diameter larger than the diameter of saidholes which are formed in the two pole pieces and the magnet.

7. In a magnetic catch, a permanent magnet sandwiched between polepieces and each comprised of a flat plate of rectangular planconfiguration with a hole in the center, a housing of nonmagneticmaterial formed to a general U-shape when viewed from the front toproduce a stall in which the sandwich is received, the stall having afloor and side walls and being open at least at the front and the top,said housing having a rigid hollow post with an open top rising from thefloor of the stall and fitting loosely through said center openings ofthe several components of the sandwich for holding the sandwich againstdislodgment from the stall, and a headed pin of nonmagnetic materialpressfitted in the hollow center of said post, the head of the pinhaving a diameter larger than the diameter of said holes which areformed in the two pole pieces and the magnet.

S. A magnetic catch as claimed in claim 7 in which the material of whichsaid housing is composed is plastic, each of the side walls having anear extending laterally therefrom and pierced with a circular hole, andscrews for mounting the housing received through said holes in the earsand sized so that the shanks are frictionally gripped thereby.

References Cited by the Examiner UNITED STATES PATENTS 749,438 1/ 1904Harrington 39 2,496,691 2/1950 Berry 292-2515 2,853,331 9/1958 Teetor292-2515 3,003,802 10/1961 Wilson 292251.5 3,155,409 11/1964 Schlissel292251.5 3,257,141 6/1966 Buus et a1 317-159 FOREIGN PATENTS 814,85510/1951 Germany. 672,928 5/1952 Great Britain.

EDWARD C. ALLEN, Primary Examiner. RICHARD E. MOORE, Examiner.

1. IN A MAGNETIC CATCH FOR HOLDING THE SWINGING DOOR OF A CABINETCLOSED, A PERMANENT MAGNET SANDWICHED BETWEEN POLE PIECES AND EACHFORMED FROM PLATE STOCK TO A RECTANGULAR PLAN CONFIGURATION, A HOUSINGOF NONMAGNETIC MATERIAL FORMED TO PROVIDE AN OPEN-FRONT STALL IN WHICHSAID SANDWICH IS RECEIVED WITH PORTIONS OF THE POLE PIECES PROJECTINGTHROUGH SAID FRONT OPENING AND HAVING MEANS FOR RETAINING THE SANDWICHIN LOOSE RELATIONSHIP WITH THE HOUSING, MEANS FOR NON-ADJUSTABLYMOUNTING THE HOUSING WITH ITS RETAINED SANDWICH UPON A WALL OF THECABINET TO HAVE THE FRONT EDGES OF SAID PROJECTING PORTIONS OF THE POLEPIECES FACE OUTWARDLY PROXIMAL TO AND GENERALLY PARALLEL WITH THE INNERSURFACE OF THE CLOSED DOOR, AND AN ARMATURE PLATE FOR THE MAGNET CARRIEDBY THE DOOR IN A POSITION TO STRIKE SAID FRONT EDGES OF THE POLE PIECESWHEN THE DOOR IS SWUNG INTO SAID CLOSED POSITION, THE ARMATURE PLATEBEING FORMED AS THE FLAT HEAD OF A SCREW HAVING A COMPARATIVELY LONGTHREADED SHANK OF A UNIFORM DIAMETER THROUGHOUT VERY NEARLY ITS ENTIRELENGTH AND; COMPOSED OF A MATERIAL ATTRACTED TO THE MAGNET AND SOTHREADABLY MOUNTED UPON SAID DOOR THAT THE ACT OF TURNING THE SCREW INONE DIRECTION ADVANCES THE HEAD TOWARD AND IN THE OTHER DIRECTIONRETRACTS THE HEAD FROM SAID INNER SURFACE OF THE DOOR, THUS TO POSITIONTHE HEAD IN A SELECTED POSITION ADJUSTED TOWARD OR FROM SAID INNERSURFACE.